Daily Kos :: Political Analysis and other daily rants on the state of the nation.
So, how do you counter a fencing attempt? Here are a few ideas, based on the above:

1. Express outrage, even if the charge is small. Make even the initial fencing attmepts appear outrageous, and explain why it is outrageous. Generally speaking, people find things outrageous when they're told other people find them outrageous.
2. Call the charge out for what it is. Make clear that the "fencer" is trying to change the subject from what actually makes a difference to people. At the same time, make those making the charges look unapproachable, unbelievable and extreme. Example: go after the Swift Boaters as a cultlike group, led by partisans, who have been feeding each other's lies for nearly a year. Make their personal motivations the center of the counterattack. Attack them on the grounds that they're lying, so who can believe anything they say? Fight fire with fire.
3. Respond to the charges immediately. Explain exactly why they're false. Play up the credibility of the target with specific examples where the "fencing" frame simply doesn't fit.
4. In combination with the other tactics, redirect the issue toward what the "fencer" wants people to avoid thinking about.
5. Laugh at the charges (different from "ignore" the charges). Make them and those who are making the charges the objects of ridicule. Does anyone actually believe this?